Async httpclient should now work. Changed recv behaviour.

asyncdispatch.recv no longer guarantees that it will read ALL the data
requested. The underlying WinAPI function doesn't guarantee this and it
already wasn't guaranteed anyway since the socket could disconnect
mid-transmission.

lib/pure/asyncnet.nim

@@ -116,7 +116,8 @@ proc recvLine*(socket: PAsyncSocket): PFuture[string] {.async.} =
     if c == "\r":
       c = await recv(socket, 1, MSG_PEEK)
       if c.len > 0 and c == "\L":
-        discard await recv(socket, 1)
+        let dummy = await recv(socket, 1)
+        assert dummy == "\L"
       addNLIfEmpty()
       return
     elif c == "\L":
@@ -148,7 +149,7 @@ when isMainModule:
     TestCases = enum
       HighClient, LowClient, LowServer
 
-  const test = LowServer
+  const test = HighClient
 
   when test == HighClient:
     proc main() {.async.} =